Lokhir fellheart should, when you play him, have essentially the same, or a similar campaign to vampire coast. this would add a very unique dark elf playstyle without too much work, just edit the way vampire coast objectives work to suit dark elves. the only problems i see are this needing cutscenes/dialogue, and new quest battles against one or all of the vampire coast legendary lords. this would also make it so he could be played in head to head with a vampire coast faction.
edit: he should also have the blessed dread as part of his army, so that he basically functions as a black arc that can go on land.